Blindstitch device for sewing-machines



APPLICATION FILED JAN.2 19!} Patented Nov. 4, 1919.

2 W J 5 4. j M

A. H. DE VOE.

BLINDSTITCH DEVICE FOR SEWING MACHINES.

APPLICATION FILED JAN.2 1917 1,320,457. Patented Nov. 4, 1919.

2 SHEETS-SHEET 2.

ATTORNEY ALBERT H. DE VOE, OF WESTFIELD, NEW JERSEY, ASSIGNOR TO THESINGER MANUFAC- TURING COMPANY, A CORPORATION OF NEW JERSEY.

BLINDSTITQH DEVICE FOR SEWING-MACHINES,

Specification of Letters Patent.

Patented Nov. 4, 1919.

Application filed January 2, 1917. Serial No. 140,122.

following is a specification, reference being had therein tptheaccompanying drawings.

This invention relates to sewing machines equipped for blind-stitchinand has for an object to provide a machine which will simultaneouslystitch upper and lower plies of fabric together or to the opposite facesof intermediate material in such a manner that the connecting portionsof the stitching thread or threads between adjacent needlepunctures willnot be visible at either side of the seam.

More specifically the invention has for an object to provide a machinewhich will simultaneously blind-stitch upper and lower tapes together attheir opposite margins to form a tubular structure, or to blind-stitchsaid tapes to the opposite faces of intermediate body-fabric which mayinclude a previously formed seam, to be covered by said tapes, or whichmay present overlapping or abutted edge-portions to be simultaneouslyjoined and covered by said tapes as they are stitched together.

A further object of the invention is to provide means for producing afullness in a strip of material after it has passed over an invertingedge to compensate for any undue stretching of the material and toinsure that said material will be stitched to the bodyfabric in normalor unstretched condition. The invention also contemplates the adjustmentof said means to produce more than enough fullness to con'ipensate forany stretching of the material, whereby the latter may, if desired, bestitched to the bodyfabric in a rufiied condition.

A further object of the invention is to provide means for pulling theupper and lower strips of material from the supply.

Further objects of the invention will appear from the followingdescription and claims.

The invention, in its preferred embodiment, comprises a sewing machineof the usual flat-bed type having a cloth-plate over which is disposedthe usual head carrying a presser-bar and reciprocating needle-bar whoselower end terminates in a laterally extended needle-clamp carryingspaced eyepointed needles which cooperate with any suitable type ofloop-taker mechanism, in the usual manner to form spaced rows ofstitches. Secured to the Presser-bar is a presser-foot whose shank isformed with a tape-guiding slot and whose sole-portion is formed with atransversely extending tapeinverting edge which is spaced above the fabPic-engaging surface of the resser-foot and is disposed in rear of andclosely adjacent the paths of the needles.

Cooperating with the fabric-engaging surface of the presser-foot to feedthe work is any suitable type of feeding mechanism which may comprise afour-motion feed-dog operating through a slotted throat-plate. In thepresent instance the throat-plate is provided with a narrow transverselyextending slot whose opposite end-portions receive the descendingneedles and whose rear edgewall serves to invert a tape drawn forwardlybeneath the throat-plate and upwardly through said needle-receivingslot. The rear edge-wall of the needle-receiving slot and thetransversely extending forward edge of the presser-foot define a planewhich is disposed parallel to and closely in rear of the plane of theneedles, whereby the needles will split the upper and lower thicknessesof tape presented by the tape-inverting elements and connect said tapesby spaced rows of blind-stitches.

The presser-foot carries an adjustable, forwardly disposed, fulling orrufiiing blade which is actuated by the needle-bar andis directedrearwardly to engage the upper tape between the inverting element andthe last stitch and to full in said tape to the extent desired. Apull-ofi' bar carried by the presser-foot and actuated by the needlebaris adapted to draw the material closely about said element, to insureaccurate splitting thereof by the needles, and to pull the material fromthe supply. Preferably, the fulling blade is first actuated to engageand full in the material below the inverting element after which thepull-off bar is actuated to draw back any excess of material whileholding the latter close to said inverting edge.

The feed-dog of, the machine is slotted to guide the lower tape and itsrising and falling motion is taken advantage of to pull a length oflower tape from the supply prior to each feeding stroke in order thatthe tape may run freely over the lower inverting element withoutbecoming unduly stretched or offering undue resistance to the action ofthe feeding mechanism.

In the accompanying drawings forming a part of this specification;Figure 1 is a perspective view of the machine showing the work in place.Fig. 2 is a left side elevation, partly in section, with the needles attheir highest point. Fig. 3 is a similar view with the needles at theirlowest point. Fig. 4: is an enlarged cross sectional view through thepresser-foot and throat-plate. Fig. 5 is a front view showing thepresser-foot in elevation and the throat-plate and feed-bar in section.Fig.6 is a horizontal section of the presser-foot and needles on theline 5-5, Fig. 5. Fig. 7 is a bottom plan view of the resser-foot. Fig.8 is a plan view of a portion of the throat-plate. Fig. 9 isan enlargedsectional view similar to Fig. 4 but showing a modification of theinvention and Fig. 10 is a perspective view of a seam formed by themachine.

In the embodiment illustrated, the invention comprises a flat-bed sewingmachine of usual construction having a cloth-plate 1 over which isdisposed the head 2 carrying the usual spring-pressed resser-bar 3 andreciprocating needle-bar whose lower extremity is extended laterally toform a needle-clamping head 5 in which are secured, in spaced relation,the eye-pointed needles 6 which may coiiperate with any of the wellknownloop-taker mechanisms to produce spaced rows ofstitches.

Secured to the presser-bar 3 by the screw 7 is the slotted lug 9 whichpro ects rearwardly from a tape-guiding frame comprising a verticalplate 10 whoselower'end-pon' tion together with the lug 9 form the shankof a presser-foot 11.

Secured within a recess in the bottom face of the presser-foot 11 by ascrew 12 is a fiat guide-block 18 whose forwardly disposed marginalportion is undercut at 13 to form a thin overhanging blade 14: whoseforwardly disposed edge-portion let may be considered as atape-inverting element which is spaced above the plane of thefabric-engaging surface of the Presser-foot and is disposed in avertical plane at right angles to the line of feed and closely adjacentand parallel to the plane of the needles 6. The lower front, corner 15of the guide-block 13 forms another tape-guiding element spaced belowand rearwardly from the tape-inverting element 14 for a pu OSe to bedescribed. The thickness of the guide-block 13 is made less than thedepth of the recess into which it is fitted to provide a tape-receivingguideway 16 in the bottom face of the presserfoot.

Extending forwardly at opposite sides of the presser-foot and atopposite ends of the tape-inverting element 14 are the spacedoverhanging toe-portions 17 which serve as edge-guides for the uppertape. The toeportions 17 are disposed above the plane of the bottomsurface of the presser-foot 11 to permit passage of the reciprocatoryfulling or rufiiing blade 18 beneath the inverting element 14! andacross a plane defined by said element 14: and the corner 15, to full inor ruflie the tape.

The fullirig or ruflling blade 18, which may or may not be toothed atits active edge 19, is carried at the lower reversely curved end'of alever 20 pivoted at its upper end between the spaced cars 21 projectingupwardly from the plate 10. Pivoted to the lever 20 at 22 is a bar 23whose slotted lower end portion is secured in adjusted position againstthe side face of the lever 20 by a screw 24. A pair of coil-springs 25projecting forwardly from suitable sockets in the plate 10 urge saidlever to the position shown in Fig. 2. As the needle-bar descends theneedle-clamping head 5 will strike the inclined front edge 26 of theadjustable bar 23 and force the fulling lever 20 to the osition shown inFig. 3. The length 0 the fulling or rufiling stroke of the blade 18 i at29 to the plate 10 and whose lower or 10- tive portion 28' is bent toassume a substantially horizontal position transversely of and above thesole-portion of the presserfoot 11. A coil-spring 30, projectingforwardly from a suitable socket in the plate 10, urges the pull-oil bar28 to initial position, as shown in Fig. 2. The head after havingdeflected the fulling lever 20 to a position in which the front edge 26of the adjustable bar 23 isparallel to the path of re.-

ciprocation ofsaid head, strikes the pull-ofi' lever 28 and deflects itrearwardly thus causing the horizontal or active portion 28 of saidlever to deflect the upper tape 2% at a point between, the tape-guidingaperture 31 and the tape inverting element 14. Deflection of the tape itat this point serves to draw said tape snugly against the inverting edge14 for penetration by the needles 6 and also serves to pull a length of,be loosened to be free] tape from the supply through the aperture 31.The horizontal portion 28 of the pulloff lever 28 is notched at 32 toreceive the needles during the first part of their down stroke.

In the present construction provision is made for passage of the undertape 2" forwardly beneath the-cloth-plate 1 and upwardly about the rearedge wall of a transverse needle-receiving slot. Supported by thecloth-plate 1 is the throat-plate 33 formed with feed-do receiving slots34 and transversely recesse in front of said slots to receive anauxiliary throat-plate 35 provided with a narrow slot 36 to receive theneedles 6 and under tape 25. The rear edgewall 37 of the slot 36constitutes an under tape-inverting element which is parallel with theupper inverting element 14 and, like the latter, is locatedsubstantially at the stitching point. In other words, the tapeinvertingelements 37 and 14' define a plane which is arallel to and closelyadjacent the plane of t is needles 6. Screwed to the under surface ofthe auxiliary throat-plate 35 is a tape-supporting plate 38, Fig. 4,whose rear edge-portion extending under theslot 36 is beveled at 39 andnotched at 40, 40, Fig. 8, to receive the needles 6. The bevelededgeportion 39 serves to support the tape t close to the under surfaceof the auxiliary throat-plate 35 and causes said tape to be bent sharplyabout the inverting element 37.

Means are provided for pulling the under tape t from the suppl in orderthat said tape maybe free to e drawn upwardly through the slot 36 whenthe work is fed. In the present embodiment the usual fourmotion feed-bar41 carrying the feed-dog sections 42 is formed with a substantiallyhorizontal tape-guiding slot 43 extending under said feed-dog sections42 and serving to guide the tape running forwardly through thepassageway 44 beneath the cloth plate 1. When the feed-bar drops at theend of a feeding stroke it will deflect the length of tape t between thepassageway 44 and slot 37 and pull a length of tape from the supplythrough said passageway. When the feed-bar rises from the position shownin Fig. 3 to begin a feeding stroke the tape will drawn through the slit36 as the work is ed.

In the modification of the invention illustrated in Fig. 9 the tapeengaging element 15, which is analo 'ous to the corner 15 in Fig. 4, isprojecte forwardly beneath the tape-invertmg element 14'. Thetape-guiding elements 14 and 15 are spaced apart and are both carried bythe block 13* Which in other res ects is similar in construction toblock 13, ig. 4. The fulling blade 18' is adapted to pass between saidelements and is provided with a non-toothed tape-engaging edge 18*. Inthis form of the invention the fulling action of the blade is obviouslyincreased and amounts practically to a ruffiin action.

V hile the machine isobviously operative without the describedtape-fulling and pulloff devices, the provision of some such devices isdesirable in order that tape which stretches easily, such as bias woventape, may be incorporated in the finished scam in a normal orunstretched condition. The fulling blade 18 accomplishes this resultwith regard to the upper tape t. The pullofi devices serve to supplyloose tape to avoid undue stretching thereof when drawn over theinverting elements 14 and 37 during a feeding action. Said devices alsoserve to draw the tapes snugly about the inverting elements forresentation to the descending needles. W en it is desired tosimultaneously join and cover the marginal portions of two pieces ofbody-fabric the machine may be provided with a-fabric guide,

- ginal portions to the needles.

In Fig. 10, which illustrates a seam formed by the above describedmechanism, the marginal portions a and a of the pieces of body fabricare folded inwardly and 'joined by means of the upper and lower tapes tand t which are connected together by the spaced rows of stitchescomprising spaced'series of keyed, penetrative, threadloop structures 8and connecting thread portions 8' extendin along the hidden, surfaces ofsaid tapes. ach of the enetrative thread-loop structures 8 passes trough the intermediate body-fabric material and enters and emerges fromthe inner or hidden surfaces of the upper and lower plies of material tand t, preferably without showing at the outer or visible surfacesthereof.

It is to be understood that the form and arrangement of the variousparts disclosed are susceptible of material modification.

without departure from the invention.

Having thus set forth the nature of the invention, what I claim hereinis -1. In a sewing machine, in combination, stitch-forming mechanismincluding a reciprocatin'g needle, feeding mechanism, and upper andlower tape-inverting elements having tape inverting edge-portionslocated substantially at but slightly in rear of the stitching point ina plane parallel to the needle and at substantially right angles to theline of feed. I

2. In a sewing machine, in combination, stitch-forming -mechanismincluding spaced parallel reciprocatingneedles, feeding mechanism, andupper and lowertape-inve'rting elements havi tape inverting edge-portions disposed in a plane in rear of and closely adjacent the plane ofsaid needles.

3. In a sewing machine, in combination, stitch-forming mechanismincluding a needle, feeding mechanism, a. guide frame having a forwardlydisposed edge about which the material to be stitched is supported forpenetration by said needle, and means moving in the direction of feed tofull in said material between said edge and the last stitch.

4:. .In a sewing machine, in combination, stitch-forminmechanismincluding a needle, feeding mec anism, forwardly directed meanslocated substantially at but slightly in rear of the stitching point forinverting a layer of fabric, and fulling in means acting in thedirection of feed on the inverted portion of said fabric between theinverting means and the stitching point before it is stitched.

5. Ina sewing machine, in combination, a throat-plate, stitch-formingmechanism. including a needle, feeding mechanism,separate elementslocated above and below the plane of said throat-plate andsubstantiallyat the stitching point for invertin upper and lower plies of fabric, andfu ling in means acting on the inverted portion of one of said pliesbefore it is stitched.

6. In a sewing machine, in combination, stitch-forming mechanismincluding a reciprocating needle, a. presser-member havin awork-engaging surface and, formed wit an edge-port1on extendingtransverse to the line of feed about which the material to be stitched.is folded for penetration by said needle, and a fulling device actingupon the material between said edge-portion and work-engaging surface.

7. In a sewing machine, in combination, stitch-forming mechanismincluding a reciprocating needle, feeding. mechanism, means locatedsubstantially at the stitching point for inverting upper and lowerstrips of fabric, and pull-oil? devices acting, respectively, on each ofsaid strips between said inverting means and"the supply.

-8. In a sewing machine, in combination,

, stitch-foi-ming mechanism including a reciprocating needle, feedingmeans including a plate having a forwardly disposed ed e locatedsubstantially at the stitching point for inverting a strip of fabric, afalling device actingin the direction of feed upon said strip betweensaid inverting means and the last stitch, and a pull-off device actingupon said strip between. said inverting means and the supply.

9. In a sewing: machine, in combination,

stitch-forming mechanism including a re ciprccating needle,feedingmechanism, guide-frame having a forwardly disposed edge overwhich the material to be blindstitcbed is drawn, and a fulling devicepositioned to act in the direction of feed upon the material betweensaid edge and the titched portion of the work.

10. In a sewing machine, in combination,

mechanism,

ciprocating needle, feeding mechanism including a work-engaging member,a pressermember member to feed the work and presenting an edge overwhich the material to be blindstitched is drawn for penetration by saidneedle, and a fulling device acting upon the material between said edgeand work-engaging member.

11. In a sewing machine, in combination, a reciprocating needle, feedingmechanism including a work-engagingv member, a presser-mem'berpresenting an edge over which the material to be blind-stitched is drawnfor penetration by said needle, and a reciprocatory fulling member uponthe material between said edge and work-engaging member and timed toengage and full in the material prior to penetration thereof by saidneedle.

12. In a sewing machine, in combination, feeding mechanism including afeed-dog, a presser-foot formed with a tape-inverting edge, areciprocatory blade pivotally mounted upon said presser-foot and adaptedto engage and full in the tape below said edge, and stitch-formingmechanism including a needle adapted to reciprocate in a path closelyadjacent said edge.

'13. In a sewing machine, in combination, stitch-forming mechanismincluding a needle, feeding mechanism, a presser-foot supcoiiperatingwith said feeding acting ported in rear of said needle and having anedge-portion for inverting a strip of material while presenting it tosaid needle, and

a reciprocatory fuliing blade adapted to pass beneath said invertingedge-portion at the end of its fulling stroke.

14: In a sewing machine, in combination,

a"rciprocating needle-bar carryinga neestitch-forming mechanismincludingv a re- 7 ciprocati-ng needle, a presser-member having spacedwork-guiding surface portions one of which is disposed closely ad acentthe needie-path, whereby the material to be biindstitched is presentedfor penetration by the needle, and a fulling device aving anoperativeedge adapted to cross a line connect ing said surface portions.

16. In a sewing machine, in combination, stitch-forming mechanismincluding a re ciprocating needle, feeding mechanism, a throat-platehaving a needle -aperture through which the material to be stitchedpasses upwardly and is presented in a transversely folded condition forpenetration by said needle, and means sustained below said aperture forsupporting the fold of material against the thrust of said needle.

17. In a sewing machine, in combination, stitch-forming mechanismincluding a reciprocating needle, feeding mechanism, a throatplatehaving a needle aperture through which the material to be stitchedpasses upwardly and is presented in a trans said strip between theneedle apertureand the source of supply.

.19. In a sewing machine, in combination, stitch-forming mechanismincluding a reciprocating needle, four-motion feeding mechanism, athroat-plate having. a needle aperture through which a strip to bestitched passes upwardly, and means whereby an element of said feedingmechanism serves as a pull-ofi' for said strip prior to a feedingstroke.

20. In a sewing machine, in combination, stitch-forming mechanismincluding a reciprocating needle, feeding mechanism including afeed-bar, a throat-plate, and s aced. strip-guiding elements below thewor engaging surface of said throat-plate, saidfeed-bar being adapted toengage and defiect said strip between said elements.

In testimony whereof, I have signed my name to thislspecification.

ALBERTH. DE VOE.

